199. Matthew Yglesias Why is American Politics Uni-dimensional?
August 4, 2009 § Leave a comment
We are unidimensional.W hy? it is the way to make the economic issue central and the poor lose, big business wins. The reality is that the parties are bi-dimensional (between and within turns out) whereas the electorate is polydimensional on many isues of consequence, butalso more unified, like thinking the bank bonuses wrong, which are not allowed into the political debate. For more on this see my chapter on the american political scene, Is religion a way of saying no?
Why is American Politics Uni-dimensional?
Paul Krugman briefly mentions a somewhat intriguing puzzle. Most people, if you ask them about it, would say that political beliefs are “multidimensional.” We often think of a simple 2-dimensional models like the Nolan Chart in which people should be sorted along both a left-right axis about economics, and then along a second axis about social/cultural issues like gay rights. But as Krugman observes, Congress doesn’t work this way:
That’s what I would have thought a few years ago. But then I became familiar with the Poole-Rosenthal work on Congressional voting. They use a clever algorithm to jointly map bills and members of Congress in a hypothetical issues space. The number of dimensions in that space is arbitrary — but they found that historically just two dimensions accounted for the great bulk of voting. One dimension corresponded to left-right on economic issues; the other was basically race/segregation.
And since the 1960s, with the great Southern realignment, the race dimension has collapsed. So Congressional politics is left versus right — end of story. Oh, and polarization along that dimension has increased hugely: the center did not hold, and there really isn’t any middle ground.